(1) Field of Invention
The present invention relates to a microcomputer system for communicating data or signals via an optical fiber cable, and more particularly to a microcomputer system for use in controlling an electrophotographic copier having a number of noise-generating sources.
(2) Description of the Prior Art
An electrophotographic copier utilizing an electrophotographic processing as an example of the recording apparatus generally includes a plurality of microcomputers for effecting a multi-microcomputer system control, wherein each microcomputer controls such operations as scanning, electrophotographic processing or the like with the microcomputers communicating control data with each other.
The above-noted type of recording apparatus incorporates therein a number of sources tending to generate various electric noises such as those from high-voltage power sources represented by chargers, static electricity generated in association with copy sheet movements or with toner (conductive material) movements. For this reason, such apparatus needs to be provided in its electric circuits, harnesses or the like with various precautionary measures against the electric noises.
With a view to the above situation, the prior art has suggested use of an optical fiber cable as the data communication line in an attempt to combat the noise problem.
When an optical fiber cable is utilized for data communication between microcomputers, it has been a common practice to solder data-communicating terminals of the microcomputer to a printed circuit board and to connect these soldered terminals via a printed pattern to terminals, which are also soldered to the printed circuit board, of an optical interface device interfacing the microcomputer with the optical fiber cable. That is to say, at the data output side, an electric signal generated from a serial data output terminal of the microcomputer travels through the electric circuit on the printed circuit board to reach the optical fiber interface device, where the electric signal is converted into optical data with a light emitting diode being energized by a driver, and then the data are transferred via the fiber cable to another microcomputer. Similarly, at the data input side, the optical data is converted through a photodiode, amplifier and comparator into electric data to be input to a serial data input terminal of this microcomputer.
With the above-described prior-art system utilizing the optical fiber cable as a noise-combatting measure; however, the signal is temporarily converted into an electric signal to be input to the microcomputer via the printed pattern and the photocopler both of which are exposed to the ambient conditions. Therefore, there remains the problem of the vulnerability of the exposed parts to the electric noises.